Evaluation of nitrogen availability indices and their relationship with plant response on acidic soils of India

Abstract

Plant's nitrogen (N) requirement that is not fulfilled by available N in soil has to be supplied externally through chemical fertilizers. A reliable estimate of soil N-supplying capacity (NSC) is therefore essential for efficient fertilizer use. In this study involving a pot experiment with twenty acidic soils varying widely in properties, we evaluated six chemical indices of soil N-availability viz. organic carbon (C org ), total N (N tot ), acid and alkaline-KMnO 4 extractable-N, hot KCl extractable-N (KCl-N) and phosphate-borate buffer extractable-N (PBB-N), based on their strength of correlation with available-N values obtained through aerobic incubation (AI-N) and anaerobic incubation (ANI-N), and also with the dry matter yield (DMY), N percentage and plant (maize) N uptake (PNU). In general, the soils showed large variability in NSC as indicated by variability in PNU which ranged from 598 to 1026 mg/pot.

Biowaste Utilisation for Improving Soil Health and Crop Productivity in North Eastern India

“…Although, the soils of north-eastern hills (NEH) contain high amount of organic matter, it does not reflect the correct estimate of available N (Bordoloi et al, 2013). The critical limit of organic carbon for such soils has been found in the range of 1.5-2.4 %, below which response of crops to N fertilizer would be more (Prasad et al, 1981).…”